Keywords: getopt, license issues, GPL, BSD, optind
Hey guys,
I mentioned some months ago about how I was using GPL's "getopt" library
in one of my company programs, and I was wondering about the GPL
distribution issues.[1]
Anyway, now I'm writing a software I want to release with BSD license,
but I also want the GNU getopt statically-linked. Since I can't do that,
I decided to write my own GNU-compatible getopt library. I know Micah
offered to do this if I wanted it badly enough, but I thought it'd be an
interesting challenge so I decided to try it myself.
The library is interestingly working really well. I wrote a test program,
and I can't tell the difference between the GNU version and mine! :) But
I've ran into a dilemma regarding how the library should behave, and I
thought I should get some feedback from this group of geniuses :)
The getopt library has the following parts:
char* optarg; (the argument to an option)
int optind; (argv[optind] will be processed at next getopt() call)
int opterr; (if true, getopt() will print error on invalid option)
int optopt; (getopt() returns this on invalid option)
int getopt(int argc, const char* argv[], const char* optstr);
(the actual getopt() call)
I implemented everything. optarg, opterr, and optopt work exactly
identical to GNU's getopt. However, optind is a little different because
my library doesn't reshuffle argv[] like GNU's getopt. That's okay with
me, but things get hairy if "optstr" doesn't have '-' as its first
character -- then the programmer is expected to search the remaining
argv[] starting with "optind"... but due to GNU getopt's flexible nature,
there could be unhandled entries in argv[] not only at the end but in the
middle, too (creating "holes" of unhandled optarg in argv[]). So where
should "optind" point to by the time "getopt" finishes processing all the
options and there are "holes" of unhandled optarg only plain strings
remain? (That's a little long and confusing; I hope you understand all
that :)
I think I now understand why GNU shuffles argv[]. But I don't need this
to be fully compatible with BSD's getopt; I just need it to behave in
reasonable manner. I'd like to hear some ideas and what you think the
behavior should be and how it's better than others.
Thanks!
-Mark
[1] - Interesting how that issue came up on Slashdot a couple days ago,
and the answers were pretty much what I got here :)
--
Mark K. Kim
http://www.cbreak.org/
PGP key available upon request.
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